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@@ -1,28 +1,47 @@
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-This directory contains the USB Tranzport and Alphatrack Kernel drivers for Linux.
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+This directory contains the Linux USB Tranzport and Alphatrack Kernel drivers.
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-At present the tranzport does reads/writes of 8 byte cmds to /dev/tranzport0 to control
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-the lights and screen and wheel
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+See http://www.frontierdesign.com for details on these devices.
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-At present the alphatrack accepts reads/writes of 12 byte cmds to /dev/tranzport0 to control
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-the lights and screen and fader.
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+Userspace test code is available from
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-Both drivers also have some sysfs hooks that are non-functional at the moment.
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+git://toutatis.isc.org/home/d/src/git/frontier.git
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-The API is currently closely tied to the ardour revision and WILL change.
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+At present the tranzport does reads/writes of 8 byte cmds to
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+/dev/tranzport0 to control the lights, screen, and wheel.
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-A sysfs interface is PERFECT for simple userspace apps to do fun things with the
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-lights and screen. It's fairly lousy for handling input events and very lousy
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-for watching the state of the shuttle wheel.
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+At present the alphatrack accepts reads/writes of 12 byte cmds to
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+/dev/tranzport0 to control the lights, screen, fader and touchpad.
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-A linux input events interface is great for the input events and shuttle wheel. It's
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-theoretically OK on LEDs. A Fader can be mapped to an absolute mouse device.
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-But there is no LCD support at all.
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+The tranzport driver provides a rudimentary sysfs interface for the status of
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+the device and a writable parameter for turning wheel compression on and off.
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-In the end this is going to be driven by a midi layer, which handles all those
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-cases via a defined API, but - among other things - is slow, doesn't do
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-flow control, and is a LOT of extra work. Frankly, I'd like to keep the
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+The API is nothing more than the USB commands issued to the device. Why?
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+
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+The control wheel/fader can generate events far too quickly for
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+a typical userspace application to keep up with them via libusb. Input
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+needs to be 100% accurate and fast in order for the alphatrack or tranzport
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+to be useful.
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+
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+UIO would be useful except that usb disconnect events need
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+to be handled correctly.
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+
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+A sysfs interface is perfect for simple userspace apps to do fun things with
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+the lights and screen. But it's fairly lousy for handling input events and
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+very lousy for watching the state of the shuttle wheel.
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+
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+A linux input events interface is great for the input events and shuttle wheel.
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+* It's theoretically OK on LEDs.
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+* A fader can be mapped to an absolute mouse device.
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+* But there is no LCD support at all, or fader feedback support in that API
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+
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+So, thus, these stubby drivers exist.
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+
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+In the end this could be driven by a midi layer, which handles all those
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+cases via a well defined API, but - among other things - is slow, doesn't do
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+flow control, and is a LOT of extra work, none of which is required at
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+the kernel level (probably). Frankly, I'd like to keep the
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core driver simple because the only realtime work really required is
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the bottom half interrupt handler and the output overlapping.
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-Exposing some sort of clean aio api to userspace would be perfect. What that
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+Exposing some sort of clean api to userspace would be perfect. What that
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API looks like? Gah. beats me.
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David Täht